Apparatus for coupling members of a well tool



Feb. 25, 1969 .1. w. KISLING m 3, ,5 0

APPARATUS FOR COUPLING MEMBERS OF A WELL TOOL Filed June 1, 1966 Sheet of 2 a V I3 f0m 6U 14/. Ms/krzg, E I INVEIVTOR JTTORVE Y Feb. 25, 1969 .1. w. KISLING m 3,

APPARATUS FOR COUPLING MEMBERS OF A WELL TOOL Filed June 1, 1966 Sheet 2 of 2 4/ INVENTOR 4TTORNE Y United States Patent OfiFice 3,429,590 Patented Feb. 25, 1969 3,429,590 APPARATUS FOR COUPLING MEMBERS OF A WELL TOOL James W. Kisling HI, Houston, Tex., assignor to Schlumberger Technology Corporation, Houston, Tex., a corporation of Texas Filed June 1, 1966, Ser. No. 554,518

US. Cl. 285-91 Int. Cl. F16e 25/00; F16b 7/00 6 Claims ABSTRACT OF THE DISCLOSURE This invention relates to apparatus for coupling members of a well tool, and, more particularly, to a key for positioning between members of a well tool to prevent relative rotation therebetween.

Many well tools are subjected to rotation in a well bore to perform such operations as drilling, milling, coring, etc. The above-named operations produce a force on a string of tools, which force is opposite in direction to the normal rotation of the drill string to which the tools are attached. This opposite force will be referred to hereinafter as back-off force. This so-called back-off force may produce sufficient torque on the tools in the drill string to unscrew parts of the tools from one another. Due to the construction of the tools, this unscrewing may cause separation of portions of the tool which can leave such portions stranded in the well bore. When this happens, it is necessary to perform a fishing operation to remove the portions of the tool string left in the well bore.

The efiect of the back-01f force can best be described by considering the mass and rotational inertia of a portion of a well tool. Some well tools such as jars often have portions thereof which are hanging or suspended by threads within the tool. When the tool is rotated as in a drilling or milling operations, the drill stem may suddenly be stopped as when the drill or milling tool snags or the cutter on a drill locks. In this event, the suspended portion of the well tool, because of its mass and rotational inertia, tries to continue rotating. Since the portion of the tool is hanging, a sudden stopping of right-hand rotation of the drill stem causes left-hand rotation of the thread which couples the hanging portion of the tool. If this sudden stopping of the drill stern occurs many times during several hours of operation, for example, the minute increments of movement that occur between the threaded portions of the tool finally overcome the makeup load and the hanging portion of the tool is backed off until it completely unscrews from the well tool.

It is, therefore, an object of the present invention to provide an improved apparatus for coupling members of a well tool to prevent a threaded connection between the members from backing off during the operation of the well tool in a well bore.

With this and other objects in view, the present invention includes a well tool having a portion thereof threadedly coupled to another portion of the well tool and suspended in the well tool. An aperture is formed in the outer threaded member with a groove being formed in the inner threaded member. A resilient spacer means is positioned between the ends of the two threaded members to permit alignment of the aperture with the groove while at the same time permitting the threads to be made up tightly. A key member normally having a dimension greater than the greatest dimension of the aperture is deformed to permit its insertion through the aperture into the groove. The key couples one member to the other to prevent relative rotation therebetween. Upon insertion of the key into the groove, the dimension of the key is then increased to a dimension greater than t-he dimension of the aperture to prevent its inadvertent removal from the groove and aperture. The key may be removed from the groove and aperture by once again deforming the key to a smaller dimension so that it can be removed through the aperture. 7

The novel features of the present invention are set forth with particularity in the appended claims. .The present invention both as to its organization and manner of operation together with further objects and advantages thereof may best be understood by way of illustration and ex;- ample of an embodiment when taken in conjunction with the accompanying drawings in which:

FIGURE 1 illustrates a jar for use in a string of well tools and to which the present invention is adapted;

FIGURE 2 shows the upper portion of the jar which is modified to include the present invention;

FIGURES 3, 4 and 5 illustrate a method of practicing the present invention; and

FIGURE 6 shows a perspective view of the key in a folded position.

FIGURE 1 of the drawings illustrates a well jar mechanism which is described in detail in Patent No. 3,251,426. The jar is shown having an upper sub 12 connected to a string of pipe or other well tool 14. A jar mandrel 16 is threadedly connected to the upper sub by the threaded connection at 18. A jar housing 20 is positioned about the mandrel and upper sub. The upper end of the ar housing 20 abuts an adjusting nut 22 which is threadedly attached to the upper sub 12. A shoulder 24 is provided within the inner bore of the housing and serves as an anvil for the jar mechanism. An outwardly extending shoulder 26 on the mandrel 16 serves as a hammer in the arring mechanism. A hydraulic delay mechanism is generally denoted by the reference numeral 28. Other details of the jar and its operation are best understood by reference to Patent No. 3,251,426.

The jar of FIGURE 1 is shown to illustrate a well tool which is subject to the problems set forth above. that is, the problem of back off of a member in a well tool which is threadedly suspended from another member in the well tool. In the jar described above, the mandrel 16 is threadedly connected to the upper sub 12 at 18 to provide such a suspended member and is, therefore, subject to the problem of back off as described heretofore.

The coupling mechanism which is the subject of this invention is best illustrated in FIGURE 2 of the drawings. FIGURE 2 shows in detail an upper portion of the jar mechanism of FIGURE 1 including the upper sub 12,

the mandrel 16, housing 20 and threaded connection 18 between the mandrel and upper sub. A key mechanism in accordance with the present invention is provided to prevent relative rotation of the ,mandrel 16 with respect to the upper sub 12. The key mechanism includes a longitudinal groove 31 formed in the mandrel 16 at the upper end of the mandrel below the threaded portion. An aperture 32 is formed through an overlapping portion of the upper sub 12. The aperture 32 has downwardly and outwardly sloping wall portions 33 which extend from the inner bore of the overlapping portion of the upper sub to a point part way through the aperture. Another aperture or opening 34 is formed in the housing 20 at a point adjacent the aperture 32 in the upper sub 12.

In order to align the groove 31 in mandrel 16 with the apertures 32, 34 in the upper sub and housing, a spacer 36 and one or more Spring washers 37 are positioned between the upper end of the mandrel 16 and a lower shouldered end portion 39 of the upper sub 12. An O-ring seal is positioned in the inner wall of the upper sub 12 to provide sealing engagement between the mandrel 16 and upper sub 12. The spring washers 37 permit the threaded engagement 18 between the mandrel and upper sub to be made up tight while at the same time permitting alignment of the groove 31 with the apertures 32 and 34. Alignment of the apertures and groove permits insertion of the key 38. The key 38 is shown positioned in the aperture 32 and groove 31 in an expanded or unfolded condition.

The key has enlarged end portions 41 and 42 which are connected by a thin web 43 integral with and extending between the end portions. The end wall surfaces of the end portions slant downwardly and outwardly to conform with the slanting portion 33 of aperture 32 in upper sub 12. A threaded opening 44 is provided in the outer face of the key 38 for purposes to be described hereinafter.

It may be seen by the position of the key in FIGURE 2 that when the key is inserted within the aperture 32 and groove 31, the downwardly sloping shoulders on the key provide a dimension to the key which is larger than the dimension of the aperture 32 and aperture 34. Therefore, when the key is in expanded or unfolded position, as in FIGURE .2, the key will not work loose from its seat within groove 31 because the key is retained against dislodgement by the sloping shoulders.

FIGURE 6 shows the key in its folded condition for insertion into the aperture 32 and slot 31 as shown in FIGURE 2. The key may be folded by means of a special tool or by placing the key in a vise or the like to bend the key until its greatest longitudinal dimension is small enough to permit its insertion through the apertures in the housing and upper sub. The hinge or bendable center beam 43 is positioned midway between the upper and lower faces of the key in order to prevent inertia forces acting on the key from tending to bend the key back to its original shape and allow it to work itself out of the groove 31 and tapered aperture 32 to thereby disengage from the mandrel.

In its folded condition, the key may be inserted into the groove 31 as shown in the schematic illustrations of FIGURES 3 and 4. FIGURE 3 shows the folded key positioned in the apertures 32 and 34 and the outer edges of the key seated in the groove 31. A setting tool 51 is shown positioned over the key so that a hammer applied to the setting tool will force the key to unfold and seat with its lower face nested in the groove 31. This seating of the key in the groove is shown in FIGURE 5. A punch 52 may be employed to apply force against the center portion of the key as shown in FIGURE to completely flatten out the key.

In order to remove the key from the slot 31 so that the well tool may be disassembled, a tool 50 such as that shown in FIGURE 5 may be used. The tool has a threaded shaft portion 54 which is adapted to be inserted into the threaded hole 44 in the upper face of the key. The threaded shaft is attached to a long bar 55 having a fulcrum 56 positioned on its lower surface. In order to remove the key, the threaded shaft 54 is inserted into the threaded hole 44, the fulcrum 56 is placed against the outer surface of the housing 20 and force is applied to the other end 57 of the bar 55'. Such force applied to the bar will transmit an upward and inward force to the key thereby causing the key to bend around the hinge or web 43 until the longitudinal dimension of the key is small enough to permit its removal through the apertures.

Although the key mechanism described herein has been shown for use with a jar, it is readily seen that the key would have application to other well tools which have threadedly suspended members susceptive to the problem of back off. It is also seen that the configuration of the key itself might be changed and still provide the same benefit. Therefore, while a particular apparatus for practicing the present invention has been shown and described, it is apparent that changes and modifications may be made without departing from this invention in its broader aspects.

What is claimed is:

1. Apparatus for use in preventing relative rotation between inner and outer members of a threaded coupling, comprising: an elongated opening through the wall of said outer member, said opening being defined by end surfaces spaced apart to provide said opening with a first longitudinal dimension and by side surfaces; an elongated groove in said inner member being defined by end surfaces spaced apart to provide said groove with a second longitudinal dimension of greater extent than said first longitudinal dimension and by side surfaces, the complementary side surfaces defining said groove and said opening being substantially axially and peripherally aligned; an elongated key having enlarged end portions and a reduced intermediate portion about which said key can be readily bent in order to decrease its longitudinal dimension to a value less than said first longitudinal dimension to enable positioning said key in said aligned opening and slot, said key being adapted to be flattened after being positioned in said aligned opening and slot in order to increase its longitudinal dimension to a value greater than said first longitudinal dimension; and means on said enlarged portions of said key engageable with said end surfaces of said slot when said key is flattened for restraining dislodgement of said key from said opening.

2. The apparatus of claim 1 wherein said restraining means includes outwardly facing inclined surfaces on the ends of said enlarged portions.

3. The apparatus of claim 1 wherein said enlarged end portions are substantially rectangular in cross-section to provide substantial strength against shear.

4. The apparatus of claim 1 and further including means for coupling a device to said key, which device is operable to bend said key and thereby permit removal of said key through said opening.

5. A well tool subject to rotation in a well bore and including: first and second longitudinal members having overlapping end portions, an aperture in one of said end portions, a groove in the other of said end portions, a key positioned in said aperture and said groove for coupling said longitudinal members to prevent relative rotation therebetween, said key having a dimension greater than a dimension of said aperture, means for decreasing said greater dimension of said key to permit said key to be placed within said aperture, and a telescoping outer member positioned over said first and second longitudinal members, said outer member having an aperture for alignment with the aperture of one of said inner portions.

6. A well tool subject to rotation in a well bore and including: first and second longitudinal members having overlapping end portions, an aperture in one of said end portions, a groove in the other of said end portions, 9. key positionable in said aperture and said groove for 5 6 coupling said longitudinal members to prevent relative 2,937,854 5/1960 Kinley et al. 285-91 X rotation therebetween, said key having a dimension 2,993,714 7/1961 Junghanns 28752.08 X greater than the dimension of said aperture, means for 3,251,426 5/1966 Lebourg 175297 decreasing said greater dimension of said key to permit 1,007,772 11/1911 Davies 151-4 said key to be placed within said aperture, and resilient 5 FOREIGN PATENTS spacer means positioned between transverse surfaces of said end portions for permitting said aperture and groove 8,134 4/ 1399 Great f F to be aligned and at the same time permitting a tight en- 10,107 5/1892 Great Bfltamtbetw 11 ad end ort'ons. gagemen ee P 1 CARL W. TOMLIN, Primary Examiner.

WAYNE L. SHEDD, Assistant Examiner.

References Cited UNITED STATES PATENTS 185,936 1/1877 Landfear 151 5 1,077,931 11/1913 Hahn 285-91X 287-103;151 ,24 1,247,255 11/1917 Francesco 151 24 15 

